From 01373710b76f6c71c03e90302b35c0e3ccc67910 Mon Sep 17 00:00:00 2001
From: Joel Bodenmann <jbo@insane.engineer>
Date: Mon, 7 Apr 2025 15:23:02 +0200
Subject: [PATCH] gwin: Prevent multiple redraws

See https://community.ugfx.io/topic/4782-the-screen-is-redrawn-more-than-once/#comment-13706
---
 changelog.txt      | 1 +
 src/gwin/gwin_wm.c | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/changelog.txt b/changelog.txt
index 8e1cf78b..70f54cb5 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -34,6 +34,7 @@ FEATURE:    LGDP4532 driver improvements.
 FIX:        Win32 Keyboard driver now retrieves lock key states on window activate
 FEATURE:    Add SSD1312 GDISP driver
 FEATURE:    Add CH1115 GDISP driver
+FIX:		Fix multiple redraws of windows (thanks to Sergey Kushnir)
 
 
 *** Release 2.9 ***
diff --git a/src/gwin/gwin_wm.c b/src/gwin/gwin_wm.c
index a1cd8ea8..1b09bd37 100644
--- a/src/gwin/gwin_wm.c
+++ b/src/gwin/gwin_wm.c
@@ -749,6 +749,7 @@ static void WM_Delete(GHandle gh) {
 
 static void WM_Redraw(GHandle gh) {
 	gU32	flags;
+    gU32    parents = 0;    // Used to indicate whether the window (gh) has parent(s).
 	
 	flags = gh->flags;
 	gh->flags &= ~(GWIN_FLG_NEEDREDRAW|GWIN_FLG_BGREDRAW|GWIN_FLG_PARENTREVEAL);
@@ -790,6 +791,8 @@ static void WM_Redraw(GHandle gh) {
 				if (gh->parent) {
 					// Child redraw is done
 
+                    parents++;
+
 					// Get the parent to redraw the area
 					gh = gh->parent;
 
@@ -806,6 +809,11 @@ static void WM_Redraw(GHandle gh) {
 			// Clear the area to the background color
 			gdispGFillArea(gh->display, gh->x, gh->y, gh->width, gh->height, gwinGetDefaultBgColor());
 
+            #if GWIN_NEED_CONTAINERS
+                if (!parents)
+                    return;
+            #endif
+
 			// Now loop over all windows looking for overlaps. Redraw them if they overlap the newly exposed area.
 			for(gx = gwinGetNextWindow(0); gx; gx = gwinGetNextWindow(gx)) {
 				if ((gx->flags & GWIN_FLG_SYSVISIBLE)